JPS622020A - Device for supporting pivot shaft in precision rotary device - Google Patents

Abstract

PURPOSE:To increase rigidity for supporting pivot shaft and increase the speed of seeking by providing a tapered part on a pivot shaft end part which is opposite to a bearing and installing a metal hollow ring on this tapered part in the state of being pressed against said tapered part. CONSTITUTION:A tapered part 73 which is opposite to the inner ring of a ball bearing 11, is provided on the lower end part of a small-diameter shaft part 72 formed on the upper end part of a pivot shaft 7, and a metal hollow ring 12 is provided between the tapered part 73 and the inner ring of the ball bearing 11. And, a pressing member 13 is provided on the upper part of the metal hollow ring 12, which is pressed against the tapered part 73 by means of a coned disk spring 14 fixed to the small-diameter shaft part 72 by a screw 15, via the pressing member 13.

Description

[Detailed description of the invention]

[Industrial Field of Application] The present invention relates to a precision rotation device, particularly a swing arm type device, such as a pivot shaft support device for a recording disk device. [Prior Art] FIG. 4 is a side sectional view showing the structure of a conventional pivot shaft support device of a recording disk device disclosed in, for example, Japanese Patent Laid-Open No. 57-8967. In this figure, +11 is a support base, (2 is a pivot shaft to be supported, and a swing arm (not shown) is attached to it so that it can rotate in one direction. (J is a needle roller bearing, and a roller body (31) and an outer ring (32) disposed on the outside thereof.(21) is a recess formed in a part of the pivot shaft, and (4) is accommodated in this recess. The roller body (31) of the needle-shaped roller bearing (3) is constantly pressed outward by the compression spring (5).
) is done by pressing the inner surface outward. Next, the operation will be explained. When the swing arm (not shown) attached to the pivot shaft (2) rotates, a whirling force is generated due to its unbalanced mass, and along with this force, external vibrations etc. act on the pivot shaft (2) as a disturbance force. When a force acts in the X direction in Fig. 4, the pivot shaft (2) is supported by a needle roller bearing (3) consisting of roller bodies (31) and an outer ring (32), @4 When acting in the opposite direction to X in the diagram, use the pivot axis (2
First, the compression spring (5) is further compressed to be displaced by an amount shown by δ in FIG. 4, and the left end of the pivot shaft [2 in FIG. 4 comes into contact with the roller body (31). As a result, the color body (31)
and the outer ring (32) in the same manner as in the above case. In this state, the relationship between the bearing support force R and the displacement X of the pivot shaft (2) is shown in Fig. 5. In this figure, the slope of the straight line represents the -1j property. It is the stiffness of the roller body (31), and 1 is the stiffness (spring constant) of the compression spring (5) in the stiffness at -δ x x<0. Also, the stiffness at x<-δ is the case where Similarly, it is a stripe. In this case, kl is much smaller than kO). [Problems to be solved by the invention] The conventional device is configured as described above, and there is a region where the support rigidity of the pivot shaft is low, so the resonance frequency of the rotating system centered on the pivot shaft is low. However, this has hindered the speeding up of seek (speeding up the rotational control of the pivot shaft). Furthermore, the nonlinearity of the stiffness characteristics has also been a factor leading to low positioning accuracy. This invention was made to eliminate these drawbacks, and aims to provide a device that can always maintain a high supporting rigidity of the pivot shaft and enable high-speed seek. Means for Solving the Problems] One JITIL according to the present invention provides a tapered portion at the end of the pivot shaft and at the opposing portions of the ball bearing or both,
A metal hollow ring is interposed in the tapered portion, and means for pressing the metal hollow ring against the tapered portion is provided. [Operation] By interposing a metal hollow ring between the end of the pivot shaft and the ball bearing, the support rigidity of the pivot shaft in the radial direction is determined by the rigidity of the ball bearing and the rigidity of the metal hollow ring.
It is radially uniform, extremely large and stable. Therefore, it is possible to increase the seek speed of the swing arm and improve the positioning accuracy. [Embodiment of the Invention] J2t'F, an embodiment of the invention shown in FIG. 1 will be described. In this figure, (6) is No Kujin, (7
) is the pivot shaft, and its lower end (71) is the set screw (8)
is fixed to the above-mentioned hatching (6), and displacement in the axial direction is restrained. (9) is a ball bearing attached IN to the lower end of the pivot shaft, (10) is a swing arm fitted to the outer ring of the ball bearing (91), (11) is a ball bearing attached to the upper end of the pivot shaft and the swing arm The ball bearing mounted on the arm [10] connects the pivot shaft (7) and the swing arm (1).
0) are mutually rotatably mounted. (72) is the thin shaft part formed at the upper end of the pivot shaft, and an enlarged view including that part and the adjacent part is shown in Figure '@2 ◎ That is, (73) is the thin shaft part. (7
2) At the lower end, a tapered part is formed in the part facing the inner ring of the ball bearing (11), and as shown in the figure, the gap between the inner ring and the ball bearing (11) decreases as it moves toward the F direction. (12) is a metal hollow ring inserted between the taper part (73) and the inner ring of the ball bearing (11), and (13) is the metal hollow ring. (12) is an indenter placed above and in contact with the indenter, (14) is the indenter

A disc spring for pressing [13] in the F direction and pressing the metal hollow ring (12) against the tapered part (73), (45J is a disc spring for pressing the disc spring against the thin shaft part (72).
) is used to fix the disc spring (14) in a flexed state so as to apply sufficient pressure to the indenter (13). Also, in Figure 1 (1
6) is a spacer placed on the top of the ball bearing (11),
It is composed of a hollow body with an inverted U-shaped cross section, and a hole (161
) is formed. (17) is a disc spring arranged above the spacer,
A hole (171) is also formed in its center. (18) is a screw screwed into the hack ring (0), which presses the spacer (16) through the disc spring (17) and applies preload in the F direction to the ball bearing (11). A hole (181) is also formed in the center of the screw (18), and the hole (171) in the disc spring and the hole (171) in the spacer are connected to each other.
161) and the screw (18), and by inserting a screwdriver or the like from outside the hack ring through each of these holes, the screw (1
5) The tightening force can be adjusted. The assembly of this device is performed in the following steps. First, the ball bearing (9) is fitted onto the pivot shaft (7). Next, the swing arm (10) is attached to the ball bearing (9), and the ball bearing (11) is attached to the swing arm. At this time, the pivot shaft (7) and the ball bearing (11) are not bonded. The tapered part (73) of the pivot shaft (7) and the ball bearing (1)
1) A hollow metal ring (12) is interposed between the metal hollow ring (12) and the metal hollow ring (12) is pressed down with an indenter (13). Furthermore, the indenter is pressed down with a disc spring (14) to the extent that it does not wobble, and the screw is screwed with the disc spring (14) being flexed.

Fix by [15]. In this state, assemble the assembly of the pivot shaft (71) and the swing arm (IOJ) into the hack ring (6), and attach the pivot shaft (71) to the F end (71
) with the set screw (8). After that, the ball bearing (11
) is held down by a spacer (16), and the spacer (16) is further held down by a disc spring (17), which is fixed with a screw (18) so as to maintain the disc spring in a prominent position. Finally, screw (18), disc spring (17) S and spacer (
The screw (15) is rotated through each of the holes (181), (171), and (161) in the spring (16) to adjust the deflection of the disc spring (14) and thereby adjust the downward force. Next, the operation of this embodiment will be explained. For ease of explanation, an enlarged side sectional view of the peripheral portion of the metal hollow ring (12) is shown in FIG. The metal hollow ring (12) has a circular cross section before insertion, but when inserted, it has a shape formed by the tapered part (73) of the pivot shaft (7), the ball bearing (11), and the indenter (13). undergoes plastic deformation. This deformation is made with a force greater than the pressing force of the disc spring (14) during assembly. this is,
This is to prevent plastic deformation from progressing any further even if a force greater than the pressing force of the disc spring (14) is applied to the metal hollow ring (12) during assembly. In other words, the metal hollow ring (12) is in a state of elastic deformation. ) and the ball bearing (11), respectively, receive forces F, , FL.If the force F is constant, these forces FP #
Li'L changes as the taper angle θ changes. In other words, if θ becomes smaller, 'P*'L becomes larger, and θ
As F'P and E'L become larger, F'P and E'L become smaller. From the above, the metal hollow ring (12) will act as a so-called wedge, and with a small pressing force, large forces FP and E'L will be transferred to the pivot shaft (7) and the ball bearing (12).
1) can be given to each. In addition, since the metal hollow ring (12) is always pushed downward, it is always elastically deformed and in contact with the pivot shaft (71) and the ball bearing (11). Rigidity is determined by ball bearings (11) and metal hollow rings (1
2) Since it consists of the rigidity of the pivot shaft (7), it has uniform (linear) and high rigidity in the radial direction. Furthermore, because of this elastic deformation, even if the gap between the pivot shaft (7) and the ball bearing (ll) increases or decreases when the temperature around the shaft changes, it will not change. As the metal hollow ring (12) also deforms elastically, it is possible to press the pivot shaft (7) and the ball bearing (11) with a nearly constant force. In other words, it is difficult to create a gap between the pivot shaft (η) and the ball bearing (11). It also facilitates adjustment to apply pressure in the radial direction to the ball bearing (11). In the embodiment of 1.l:5, the tapered part (73) is formed on the pivot shaft 171, but it may also be formed on the ball bearing (11).
11) may be formed on both sides. Furthermore, the disc spring (14) may be a spring of another configuration such as a coil spring (and the ball bearing may also be a bearing of another configuration such as a roller bearing.Furthermore, in the above embodiment, Although the case of a recording disk device has been described, it can be similarly applied to record players and other precision rotating devices. [Effects of the Invention] The present invention is constructed as described above, Since the rigidity can be increased and stabilized, it is possible to speed up the seek of the swing arm and improve the accuracy of determining the i! position.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing one embodiment of the present invention, FIG. 2 is an enlarged side sectional view of the upper end of the pivot shaft in the above embodiment, and FIG. 3 is an explanation for explaining the operation of the above embodiment. 4 is a side sectional view showing the configuration of a conventional device, and FIG. 5 is an enlarged side sectional view of a conventional f! FIG. 3 is a characteristic diagram showing the pivot shaft support rigidity depending on the position of the pivot shaft. In the figure, (1) is the support pace, [21, +71 is the pivot shaft, +31 is the needle roller bearing, (31) is the roller body, (32)
is the outer ring, (21) is the recess, (4) is the indenter, (5) is the compression spring, (0 is the hack ring, (8) is the set screw, +91
. (11) is a ball bearing, (lO) is a swing arm, (72
J is a thin shaft part, (73) is a tapered part, - (12) is a metal hollow ring, (13) is an indenter, (b). (17) is a disc spring, (16) is a spacer, (18) is a screw , (161), (171), and (181) are holes. The same reference numerals indicate the same or corresponding parts. Agent: Patent Attorney Masuo Oiwa Figure 1 13 - Indenter 161, 171, 181 : Figure 2 of the hole Figure 4 of the hole Figure 5

Claims (1)

[Claims] 1. In a swing arm type precision rotation device in which a pivot shaft is supported by a bearing, a tapered portion is provided at the end of the pivot shaft and one or both opposing portions of the bearing; 1. A pivot shaft support device for a precision rotation device, characterized in that a hollow metal ring is interposed therein, and means for pressing the hollow metal ring against the tapered portion is provided. 2. The pivot shaft support device in a precision rotation device according to claim 1, wherein the pressing means is a disc spring mounted on the end of the pivot shaft. 3. A pivot shaft support device in a precision rotation device according to claim 1, wherein the pressing means is a coil spring.